This invention relates generally to remote chemical and biological analysis and, more particularly, to remote analysis of materials contained within cryogenic surfaces. An application of particular interest is the remote exploration of planets and their moons. The US National Aeronautics and Space Administration (NASA) is planning a Jupiter Icy Moons Orbiter (JIMO) to explore the nature and extent of habitable environments in the solar system. One of the main objectives of the mission is to detect and analyze a wide variety of chemical species, including chemical elements, salts, minerals, organic and inorganic compounds, and possible biological compounds, in the surface of Jupiter's icy moons.
One possible technique for analysis of icy moon surfaces is laser-induced breakdown spectroscopy (LIBS), in which a powerful laser beam is used to ablate material from a surface area of interest. A spectrometer is used to analyze electromagnetic emissions that ensue during a very brief time interval following ablation of the surface material. Many materials can be identified by this technique because all elements emit light when excited to sufficiently high temperatures. The only limitations are the power of the laser and the sensitivity and frequency range of the detector and spectrometer. The most significant drawback of using LIBS for exploration and analysis of planetary bodies is that a laser irradiance of about 1 GW/cm2 is required. Even in a space vehicle with relatively high internal power generation resources, such as onboard nuclear power, using a laser this powerful is a practical impossibility. The LIBS technique is further limited to analysis of chemical elements. Chemical compounds become fragmented under a plasma breakdown condition that is inherent in the ablation process.
Remote analysis of gas and aerosol clouds is a relatively well known technology. For example, U.S. Pat. No. 6,531,701 to Mau-Song Chou et al., entitled “Remote Trace Gas Detection and Analysis” and Patent Application Publication No. US 2005/0026276, by Mau-Song Chou, entitled “Remote Detection and Analysis of Chemical and Biological Aerosols,” both disclose techniques for remotely analyzing a cloud based on spectroscopic observation of thermal emissions from the cloud as a result of a radiation beam. These techniques cannot, of course, be used directly to analyze materials that are bound to an ice matrix.
It is also known in the art that thermal spectral analysis of gases or aerosols may be enhanced by placing a cold device such that it serves as a background in the field of view of the spectrometer. Patent Application Publication No. US 2004/0259234, by Mau-Song Chou et al., entitled “Detection and Analysis of Chemical and Biological Materials,” and Patent Application No. US 2005/0056785, by Mau-Song Chou et al., entitled “Detection and Analysis of Chemical and Biological Materials by Passive Emission of Terahertz Wave Against a Cold Background Target,” both describe devices in which this technique is used.
Although the spectral analysis of thermal emissions from a gas or aerosol cloud are known in the art, this type of analysis cannot be directly applied to materials contained within an ice matrix. Prior to this invention, the only known approach to releasing materials from the ice matrix was to use the LIBS technique mentioned above. Since the LIBS technique does not preserve molecular structures and since the technique requires impractically large laser power levels, there is a need for an alternative approach for releasing and analyzing material that is bound in an ice matrix, particularly one at cryogenic temperatures. The present invention provides a convenient solution to this problem.